Lighting solutions taking into account circadian rhythm aspects are known in the art. WO2008/146219, for instance, describes methods and systems for emitting light that can provide a desired light-induced physiological stimulus and a desired luminous stimulus. The light can be controlled to vary the physiological stimulus within a predetermined first range while maintaining the luminous stimulus within a predetermined second range that is useful for a number of self and/or space illumination applications. For example, an apparatus may include a controller for controlling the drive currents supplied to a plurality of light-emitting elements having different spectral characteristics, wherein the combination of currents is controlled such that the mixed light emitted is associated with the desired physiological and luminous stimuli.
WO 2015/014936 A1 discloses a lighting unit comprising a first light source, a second light source, a first wavelength converting, a second wavelength converting element, wherein the lighting unit further comprises a transport infrastructure configured to arrange the first light source, the second light source, the first wavelength converting element, and the second wavelength converting element in a first configuration or a second configuration by transport of one or more of these, wherein in the first configuration and the second configuration the lighting unit provides lighting unit light having substantially the same color point while having different color rendering indices. With such lighting unit, it is possible to switch between high CRI-low efficiency and low CRI-high efficiency at a given color temperature (or color point).